You can set up a simple if statement to find out if it's empty by doing...

if ($current->isEmpty()) {

Following should work if you want to use try/catch

use Illuminate\Database\Eloquent\ModelNotFoundException;
...
try {
  $current = Promovote::where('module_id',$data['module'])->firstOrFail($id);
} catch (ModelNotFoundException $ex) {
  // Error handling code
}

Rewritten from some of my Laravel 5.1 code.

EDIT: This assumes you expect zero or one record, not multiple.

You can edit your app/Exceptions/Handler.php file by specifying a way to render certain exceptions.

public function render($request, Exception $e)
{
    if ($e instanceof ModelNotFoundException) {
        return response()->view('errors.custom', [], 500);
    }

    return parent::render($request, $e);
}

Check documentation, Errors Section.